1, 2-dicyano-1, 2-bis(n, n-disubstituted thiocarbamylthio)-ethylenes



United States Patent 3,197,472 1,2-DlCYANO-1,2-BIS{N,N-DiSUBSTlIUTEDTHIG- CARBAMYLTHitB-ETHYLENES Robert D. Vest, Wilmington, DeL, assignorto E. l. du

Pont. de Nemours and Company, Wilmington, DeL, a 5

corporation of Delaware No Drawing. Filed July 27, B62, Ser. No. 212,998

Claims. (Cl. 263-2471) This invention relates to new esters ofdithiocarbamic acids and to a process of preparing them.

The new compounds made available by this invention are 1,2dicy-anovinylene 1,2 bis-.(dithiocarbamates), also referred to herein as1,2-dicyano-l,2-bis(thiocarbamylthio)ethylenes, where each of the twothiocarbamyl nitrogen atoms is bound solely to carbon atoms. Thesecompounds are represented by the formula R s R as s Nat Q where Qrepresents one of the divalent radicals The reaction which takes placemay be represented by the following equation, usingtetracyano-1,4-dithiin as the cyclic cyanosnlfide reactant:

In this equation, the R and R have the previously ice statedsignificance and M is a cation whose dithiocarbarnic acid salt is atleast partially soluble in the inert organic medium in which thereaction is conducted.

A similar reaction takes place with the other two cyanosulfides ofFormula 1, except that, with the second one, the coproduct is apparentlya salt of 5-cyano-3,4-dimercaptois-othiazole; and that, with the thirdone, the coprodnet is a salt of 1,1-dicyano ZJ-dimercaptoethylene ratherthan of dimercaptornaleonitrile (l,2-dicyano-l,2-dimercaptoethylene) Thecyclic cyanosulfides which serve as starting materials in the process ofthis invention are the following compounds:

A. Tetracyano-1,4-dithiin,

N CO CON S B. p-Dithiino-[c]-isothiazole-3,5,6-tricarbonitrile,

C. 4,5-dicy'ano 1;3 dithiole A malononitrile, also calledZ-dicyanomethylenel,5-dicyano-1,3-dithiolene,

These various cyanosulfides can be prepared by the methods describedbelow.

A. TETRACYANO-lA-DI'DHIIN This compound has been reported in theliterature [G. Bahr, Angew. Chem. 70, 606-7 (1958)]. A very good methodfor its preparation is described in U. S. Patent 3,008,967 to Blornstromand Smith. It can also be prepared by the method described under (B)below.

13. pDITHIINO- [c] ascrnmzomspn- TRICARBONITRILE This product isobtained, together with tetracyano-L4- dithiin, by reaction of disodiumdimercaptomaleonitrile with 1,2-dichloro-1,2-dicyanoethylene. The latteris prepared by known met-hods (U. S. Patent 2,443,494) and it can beused either in the cis form (dichlorornaleonitrile) or in the trans form(dichlorofurnaronitrile). Disodium dimercaptomaleonitrile is describedin the literature [Bahr and Schleitzer, Ber. 90, 438 (1957)].

A typical preparation is as follows:

To a stirred and cooled suspension of 22.2 g. of disodiumdimercaptornaleonitrile in 350 ml. of 1,2-dimethoxyethane was added 17.4g. of dichlorornaleonitrile. An exothermic reaction occurred and themixture became deep red in color. Stirring was continued at roomtemperature for 72 hours. The suspended solid material was collected byfiltration and washed with a little 1,2-dimethoxyethane. This solidconsisted largely of sodium chloride and sulfur. The filtrate Wasevaporated to dryness in a stream of nitrogen. The solid residue soobtained was extracted with 500 ml. of warm /CN C=C benzene, giving asolution and a crystalline residue sparingly soluble in benzene.Sublimation of the solid resi due at 140-150 C. and 1 mm. pressure gave6 g. of somewhat impure tetracyano-l,4-dithiin, M.P. 196198 C.Recrystallization from hot benzene gave 5.5 g. of the essentially purematerial, M, P. 207-208" C.

The benzene extract obtained as described above was evaporated to abouthalf its original volume and cooled in ice. 'lhere was collected 10.2 g.of a yellow crystalline product, M.P. 174-176 C. 'An additional 3.1 g.of this product was obt ained from the filtrates for a total yield of13.3 g. Recrystallization of this material from benzene gave purep-dithiino- [c] -isothiazole-3,5,6-tricarbonitrile as yellow needles,M.P. 18l-l82 C.

Analysis.Calcd for C N S C, 38.69; N,22.56; S, 38.74. Found: C, 39.46;N, 22.59; S, 38.58.

Spectral analysis of this product shows the following characteristicabsorption bands:

Infrared: 4.49,u (strong), 6.50 1. (strong), 6707i, 7.'62,u (strong),8.60 (strong), 8.70,u, 8.90 9.70 10.0,u,

10.51 12.17 and 12.32,. (strong). 7

Ultraviolet y in CH Cl 240 m (2: 11,400);

268 mp $6950 285 mp. (15:7950); 33 mp. 6:19, 7

500); and a possible shoulder at 3 50 mg (ez3850).

C. 4,5-Dicyan0-1,3-dithiole-A -malononitrile' s 01 01 SK ON No C/ ON h=c1+ :3 No 1 'o=o +2KO1 ON ON s1: ON, ON

A typical preparation is as follows:

(1) DIPOTASSIUM 1,1-DICYANO-2,2-DIMERCAPTO- ETHYLENE In a one-liter,three-neck flask fitted with a stirrer, thermometer, and dropping funnelwas placed a solution of 60 g. of potassium hydroxide in 650 ml. ofdenatured ethyl alcohol. The solution was cooled to 0 C. and 35.4 g.(0.536'mole) of freshly distilled malononitrile was added all in oneportion, followed by the dropwise addition of 41 g. of (0.54 mole) ofcarbon disulfide at 0- 10 C. Toward the end of the addition, acanary-yellow salt began to percipitate. After stirring for one hourmore at 0-5 C. the solid was collected on a filter and washed with 50ml. of cold ethyl alcohol. After drying to'constant weight at 80 C. andless than 1 mm, pressure, there was obtained 109 g. (94%) yield ofdipotassium l,l-dicyano-Z,Z-dimercaptoethylene as a yellow water-solublesolid which did not melt below 250 C. Analysis.Calcd for C N S K C,22.01; S, 29.36. Found: C, 21.76; S, 29.23. 1

(2) 4,5-DICY'ANO-1,3-DITHIOLEA -MALONONITRILE To a solution of 2.50 g.(0.0115 mole) of dipotassium 1,1-dicyano-2,2-dimercaptoethylene in :50ml. of methanol was added in one lot 1.47 g. (0.01 mole) ofdichlorofumaronitrile at room temperature. After stirring for 15 4 inpreparing the products of the invention is tetracyano- 1,4-dithiin,which is readily prepared from inexpensive reactants (carbon disulfide,sodium cyanide and chlorine). The second reactant in the process of thisinvention is a salt of an N,N-disubstituted dithiocarbamie acid, i.e.,a. compound of the formula R\ u NOSM II R a s where R, R and M are aspreviously defined. Suitable cations (M) are alkali metal and alkalineearth metal cations, the ammonium cation, and alkylandalkylenesubstituted ammonium cations of the formula Ra +H2N/ V Rhwherein each of R and R is alkyl of 1-6 carbons and R,,

of the dithiocarbamate being used does not participate in the reactionand appears unchanged in the reaction product, any of the known dithiocarbamates can be used in the process. For example, R and R can bemonovalent (alike or diflferent) hydrocarbon (alkyl, 'alkenyl, alkynyl,

minutes, the reaction mixture was poured into 300 ml. of

water and the solid which precipitated was collected on a filter (1.12g.). treatment with decolorizing carbon yielded 0.99 g. of

Recrystallization from hot toluene after Found: C, 43.97; S, 30.01,

Further recrystallization from toluene gave a product of somewhat highermelting point (2l2-2l4 C.).

Of these three cyanosulfides, the preferred one for use cycloalkyl, arylgroups or combinations of such groups, e.g., aralkyl, aralkenyl oralkaryl) of up to 10 carbons joined to the thiocar-bamyl nitrogenthrough carbon, and any of these groups may bear an essentially inertsubstituent, i.e., a substituent that has substantially no tendency toreact with the cyclic cyanosulfide under the operating conditions, thetotal number of carbons including the substituent being up to "10.Examples of such substituents are ether (OR"), cyano (CN), hydroxyl(--OH) and ester (-'-COOR"), R representing a hydrocarbon group of 1-6carbon atoms, preferably alkyl.

For practical reasons of accessibility and cost, the preferreddithiocarbamates where the Rs are monovalent groups, are those in whicheach of R and R is hydrocarbon, e.g., alkyl of 1-10 carbon atoms,alkenyl or alkynyl of 310 carbon atoms, cycloalkyl of 5--10 carbonatoms, or aryl, aralkyl or alkaryl of 6-10 carbon atoms.

The dithiocarbamate reactant can also be one in which the thiocarbamylnitrogen (again attached only to carbon atoms) is a member of a ring, Rand R being joined together. Dithiocarbamates of this type may berepresented by the formula.

Z N-C--s-M \J g where Z contains 410 carbons and is an alkylene group orsuch a group in which one internal chain carbon atom is replaced by anoxygen atom, i.e., an oxaalkylene group. The most readily accessible,and therefore preferred, dithiocarbamates of this type are those wherethe divalent radical Z is alkylene of 45 chain carbon atoms and a totalof 4-10 carbon atoms, 3-oxa-l,5-pentylene, or alkylsubstituted3-oxa-1,5-pentylene having a total of 4-10 carbon atoms.

The preferred reaction products are those obtained from the moreaccessible dithiocarbamate reactants. They are therefore those havingone of the formulas r m r U S CN JEN S where R, R, and Z have thesignificance discussed in the two preceding paragraphs.

The relative proportions of the two reactants (cyclic cyanosulfide andsalt of an N,N-disubstituted dithiocarbamic acid) are not critical. Theyare important only to the extent that it is desired to utilize thecyanosulfide as completely as possible and to avoid complications in therecovery of the reaction product. For these reasons, it is preferable,but not essential, to use at least two moles of the dithiocarbamate permole of cyclic cyanosulfide. Most conveniently, the reactants are usedin approximately stoichiometric amount, i.e., in 2:1 molar ratio.

The reaction is exothermic, and it can therefore take place at a verylow external temperature, e.g., of the order of 50 C. The reactiontemperature is not critical, but it is preferred to adjust the operatingconditions, using external cooling if necessary, so that the temperatureof the reaction mixture does not exceed about 100 C. In general, it ismost convenient to operate at an internal temperature in theneighborhood of room temperature, e.g., in the range between about and50 C.

Since the reactants are solids, the reaction is normally conducted in anorganic liquid medium which dissolves them to at least some extent,e.g., 2% by weight. Any solvent which is substantially inert towards thereactants and reaction product is suitable for this purpose. Examples ofsuch reaction media include acyclic or cyclic ketones such as acetone,methyl ethyl ketone or cyclohexanone; acyclic or cyclic ethers such asdi-n-butyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane,tetrahydrofuran or dioxane; alcohols such as methanol, butanol andcyclohexanol; nitriles such as acetonitrile, propionitrile,benzonitrile, or adiponitrile; alkanoic acid esters such as ethylacetate, methyl propionate, methyl butyrate or ethyl benzoate; amidessuch as forrnamide, N,N-dimethylformamide, N,N-di.methylacetamide ortetrarnethylurea; nitro compounds such as nitromethane, nitroethane ornitrobenzene; sulfides, sulfoxides and sulfones such as diethyl sultide,di-nbutyl sulfide, dimethyl sulfoxide, diethyl sulfoxide ortetramethylene cyclic sulfone; and the like. The reaction medium neednot he anhydrous; in fact, it can contain considerable amounts of water.The preferred solvents, because their use facilitates the isolation ofthe reaction products, are those which are either miscible with water orreadily volatile, i.e., boil below about 100 C. The amount of liquiddiluent is immaterial provided it is sufiicient to maintain thereactants in at least partial solution.

The two reactants can be mixed all at once with suitable provisions fordissipating the heat of reaction, but it is more convenient to add oneto the other gradually in .order to avoid excessive local heating.

. 5 added to thedithiocarbamate at least partly dissolved in thereaction medium.

The reaction product can be isolated in any suitable manner. Aconvenient procedure, when the reaction medium is miscible with water,consists in pouring the reaction. mixture in water, which dissolves thedimercaptomaleonitrile derivative present in the mixture butprecipitates the 1,2-dicyanovinylene-1,2-dithiocarbamate. If desired,the reaction medium can be partly or completely removed by evaporationprior to this treatment. Another procedure consists in removing thereaction medium, then extracting the residue with a suitable solventwhich dissolves the reaction product but not the dimercaptomaleonitrilederivative. In either case, the reaction product can be purified byrecrystallization, if necessary.

As can be seen from their structure, the dithiocarbamates of thisinvention present possibilities of cis-trans isomerism, In most cases,spectral or other evidence suggests that the product is preponderantlythe trans isomer. However, no assumption regarding geometricalconfiguration will be made since the products are isomeric mixtures inmany cases.

The following examples illustrate the invention.

EXAMPLE I 1,2-dicyanovinylene-1,2-bis(dimethyldiihiocarbamute(CH3)2NCSC=C-SCN(CH3) g (EN ON S A solution of 21.6 g. (0.1 mole) oftetracyano-1,4-dithiin in 400 ml. of acetone was added over a period of1.5 hours at room temperature to a stirred solution of 31.4 g. (0.22mole) of potassium dimethyldithiocarbamate in 500 ml. of acetone. Afteran additional 1.5 hours at room temperature, the solvent was removedunder reduced pressure. The residual thick paste was poured withvigorous stirring into 2 liters of water to give a yellow precipitate of22.5 g. (71% yield) of crude 1,2- dicyanovinylene 1,2his(dimethyldithiocarbamate), also known as1,2-dicyano-1,2-bis(N,N-dirnethylthiocarbamylthio)ethylene. Ananalytical sample recrystallized from benzene melted at 164-165 C.(dec.).

Analysis.Calcd for C H N S C, 37.95; H, 3.83; N, 17.71. Found: C, 38.6;H, 4.0; N, 16.51.

The infrared spectrum showed absorption bands at 3.42s (CH), 4.5a (GEN,weak), 6.61 (C=C) and other bands at 7.12, 7.25, 8.05, 8.70, 10.32,11.55, and 12.50,. The ultraviolet spectrum showed M (ethanol) at 273 m(k:75.7), 277 m (k:55.9) and shoulders at 330 mp. (k: 19.9), and 400 m(14:6.4).

A solution of 4.32 g. (0.02 mole) of tetracyano-1,4 dithiin in ml. ofacetone was added dropwise over 30 minutes to a stirred solution of 9 g.(0.04 mole) of sodium diethyldithiocarbamate in 100 ml. of acetone atroom temperature. After stirring for one additional hour, the solventwas removed by evaporation and the residue was extracted with refluxingbenzene for 4 hours. The insoluble residue of this extraction wasdisodium dimercaptomaieonitrile. The benzene solution, after beingconcentrated and diluted with ethanol, afforded 4.05 g. (55% yield) of1,2-dicyanovinylene-1,2-bis(diethyldithiocarbamate), also known as,1,2-dicyano-1,2-bis(N,N-diethylthiocarbamylthio)ethylene, as a brightorange solid, MP. 106108 C. An analytical sample recrystallized fromdiethyl ether (in which it is very sparingly soluble) melted at 119.5-C.

Analysis.-Calcd for C H N S C, 45.13; H, 5.41; N, 15.04; S, 34.43.Found: C, 45.51; H, 5.78; N, 15.01; S, 34.40.

1,Z-dicyanovinyZena-1,2-bis(2,6-dimethyl- 4-morpholinecarbodi thioate) Asolution of 10.8 g. (0.05 mole) of tetracyano-1,4- dithiin in 150 m1. ofacetone was added dropwise over a 30-minute period at room temperatureto a stirred suspension of 22.9 g. (0.1 mole) of potassium 2,6-dimethyl-4-morpholinecarbodithioate in 100 ml. of acetone. The resulting deep redsolution was stirred for 45 minutes more and concentrated under reducedpressure to a thick paste. To this residue was added 400 ml. of waterwith vigorous stirring and the solid precipitate was removed byfiltration, washed thoroughly with water and dried under reducedpressure. There was obtained 15.8 g. (69.5% yield) of1,2-dicyanovinylene-1,2-bis(2,6-dimethyl-4-morpholinecarbodithioate),also known as 1,2-dicyano-l ,2-bs (2,6dimethylmorpholinothiocarbonylthio ethylene, as a bright yellow solid,M.P. 145-l50 C. This product [which can also be calledl,2-dicyanovinylene-l,2-

'a very weak CEN absorption (4.48m and no detectable C=C absorption at6.35

Analysis.Calcd for C H N O S C, 47.35; H, 5:30. Found: C, 47.85; H,5.41. Fraction B, M.P. 147-151" C., had an infrared spectrum in generalvery similar to that of Fraction A except that strong absorption bandswere observed for CEN (4.58 1) and (:C (6.35 characteristic of the cisisomers in this series. Its ultraviolet spectrum showed (ethanol) at 388my. (k=15.5) and 264 Ill .4. (k=22.1).

EXAMPLE IV 1,2-dicyan0 vinylene-1,Z-bis(diisopropyldithiocarbamateFollowing essentially the procedure of Example III, 21.3 g. (0.1 mole)of potassium diisopropyldithiocarbamate was reacted in acetone with 10.8g. (0.05 mole) of tetracyano-1,4-dithiin. There was obtained 12.35 g.(58% yield) of 1,2-dicyanovinylene-1,2 bis(diisopropyldithiocarbamate),also known as l,2-dicyano-l,2-bis (N,N-diisopropylthiocarbamylthio)ethylene, as a yellow solid melting at1121l6 C. The infrared spectrum of this product was consistent with theassigned structure.

. EXAMPLE V V 1,Z-dicyanovinylene-l,2-bis(1-piperidinecarbodithioate (EN(EN S A mixture of 10.8 g. (0.05 mole) of 'te'tracyano-IA- dithiin and19.9 g. (0.1 mole) of potassium l-piperidinecarbodithioate in ml. ofacetone was stirred for 4 hours at room temperature. Removal of thesolvent under reduced pressure gave a dark paste which was extractedwith boiling benzene, leaving an insoluble residue of dipotassiumdimercaptomaleonitrile. Concentrating and cooling'the benzene extractafforded 15.3 g. (77% yield) of yellow crystals of1,Z-dicyanoVinylene-1,2-bis(1- piperidinecarbodithioate), M.P. 161 C.After recrystallization from benzene, this product melted at -161 C.

Analysis.-Calcd for C H N S C, 48.47; H, 5.09; S, 32.35. Found: C,48.94; H, 5.24; S, 32.58.

The infrared spectrum supported the assigned structure. This compoundcan also be called1,2-dicyanovinylene-l,2-bis(1,5-pentylenedithiocarbamate), or1,2-dicyano-l ,2-bis- (piperidinothiocarb onylthio ethylene.

EXAMPLE v1 '1,Z-dicyanovinylane-1,2-b is(methylphenyldithiocarbamate) IIV I II CH3 s (5N ON s orn A solution of 10.8 g. (0.05 mole) oftetracyano-l,4-dithiin in 100 ml. of acetonitrile was added slowly to asuspension of 22.1 g. (0.1 mole) of potassiummethylphenyldithiocarbamate in 100 ml. of acetone'at room temperature,after which the reaction mixture was stirred for 4 hours. After removalof the solvents under reduced pressure, the pasty reaction product wasextracted with hot benzene. The dithiocarbamate has, however, limitedsolubility in this solvent since this operation left 31 g. of insolubleresidue and the benzene extracts af- 'forded only 1.2 g. of1,2-dicyanovinylene-1,2-bis(methylphenyldithiocarbamate), also known as1,2-dicyano-1,2- bis (N methyl-N-phenylthiocarbamylthio) ethylene, M.P.194-196 C. The above insoluble residue was then washed with ethylacetate, followed by extraction with water, which removed thedipotassium dimercaptomaleonitrile,1eavingan additional 14.64 g, of1,2-dicyanovinylene-1,2-bis (methylphenylidthiocarbamate). An analyticalsample was recrystillized from toluene to give bright yellow crystals,M.P. 1992'02 C. with decomposition.

Analysis.Calcd. for C H N S C, 51.51; H, 3.66. Found: C, 54.95; H, 3.38.

The infrared spectrum was consistent with the assigned structure.EXAMPLE VII The product of Example I was prepared from 4,5-di-'cyano-l,3-dithiole-A -nralononitrile.as follows:

A solution of 2.16 g. (0.01 mole) of 4,5-dicyano-1,3-dithiole-A-malononitrile in 50 ml. of acetone was added dropwise at roomtemperature to a stirred suspension of 3.18 g. (0.02 mole) of potassiumdimethyldithiocarbamate in 100 ml. of acetone, after which the mixturewas stirred for 1.5 hours. The solvent was removed under reducedpressure and the residual brown oil was stirred with 50 ml. of water,which dissolved the potassium salt of 1,2-dicyano-1,2-dimercaptoethyleneand left 1.1 g. (35% yield) of crude1,2-dicyano-1,2-bis(dimethyldithiocarbamate), also known as1,2-dicyano-l,2bis(N,N-difmethylthiocarbamylthio)ethylene. Afterrecrystallization from benzene, comparison of the infrared spectrashowed that this compound was the same as that obtained in Example I. 1

EXAMPLE VIII The product of Example I was prepared frompdithiino-[c]-isothiazole-3,5,6-tricarbonitrile as follows: To a stirredsolution of 3.18 g. (0.02 mole) of potassium dimethyldithiocarbamate in250 of acetone was added 2.48 g. (0.01 mole) ofp-ditbiino-[c1-isothiazole- 3,5,6-tricarbonitrile. After stirring fortwo days at room temperature, the solvent was removed under reducedpressure. The dark residue was extracted with boiling benzene, leaving abenzeneinsoluble material, presumably the salt of cyano 3,4dimercaptoisothiazole. Evaporation of the benzene extract afforded anoily residue which did not crystallize but which was shown to consistchiefly of 1,2-dicyanovinylene-1,2-bis(dimethyldithiocarbamate) by itsinfrared spectrum (major absorptions at 3.40, 4.5, 6.69, 7.29, 8.0, 8.7,and 102a).

A number of representative compounds of this invention have beendescribed in the foregoing examples. These examples, however, are merelyillustrative, since the invention embraces broadly the1,2-dicyanovinylene- 1,2. bis(N,N disubstituted dithiocarbamates). Othercompounds of the invention which can be prepared, in accordance with thedescribed methods, by reacting a cyanosulfide as defined above(preferably tetracyano-1,4- dithiin) with a dithiocarbamate salt asdefined above, are listed below as further illustrative examples. Thesecompounds all fall under the general formula Where R and R (which can bejoined together to form a divalent radical) have the previously statedsignificance. For the sake of brevity, only the various groups are namedin the following list:

R R N\ Group N\ Group Dibutylamlno. Ethyl (4-isopropenylphenyl)amino.Diisoamylamino. Bis(2-propoxyethyl)amino. Bis(2-ethylhexyl)amino. Ethyl(ti-methoxyhexyl) amino. Didecylamino. Ethyl (p-methoxyphenyDamino.Isopropylmethylamino. Butyl (2-eyanoethyDamino. Diallylamiuo.(Z-Cyanoethyl)eyclohexylamino.

Methyl (4pentenyl)amino. Methyl (1,1-djmethyl-2 propynyl)- ammo.Isopropyl (1,1-dimethyl-2- propynyDamino. Dicyclopentylamino.DiQS-naphthyDamino. Butylphenylamino. Allylphenylamino. Dibenzylamino.Diphenethylamino. Benzylmethylamino. Ethyl (m-toly1)an1ino. Phenyl(p-to1yl)amino. Dixylyla-mino. Cinnamyhnethylamino.

Bis(2-hydroxyethyl)amino. (5-HydroxypcntyDmethylamino.(o-Hydroxyphenyl)methylamino. (3-Carbomethoxypropyl)methylamino.(2-Carh0hexoxyethyl)ethylamino. (Z-Carbethoxyethyl) phenylamino.l-Pyrrolidyl. 2,5-Dimethyl-1-pyrrolidyl. 2-Isobutyl-l-pyrrolidyl.2,6-Diethyl-l-piperidyl. Z-Amyl-l-piperidyl. i-Morpholinyl.2-Ethyl-4-rnorpholinyl. 2,fi-Dipropyl--morpholinyl.

The 1,2-dicyanovinylene-l,2-bis(N,N-disubstituted di- 10 groups.However, it was found to be wholly ineffective as an accelerator invulcanization tests (ASTM Method D4l2-51T) conducted on sythetic rubber(25/75 st rene/butadiene copolymer), whereas the 1,2dicyanovinylene-l,2-bis(dithiocarbamates) illustrated in the foregoingexamples gave excellent results in the same tests.

In addition to their utility as rubber vulcanization accelerators, theproducts of this invention, which are all brightly colored, are usefulas dyes for natural and synthetic fibers. As an example, a solution of20 mg. of 1,2 dicyanovinylene-1,Z-bis(dimethyldithiocarbamate) in asmall amount of acetone was added to 20 ml. of water containing 20 mg.of a commercial sulfonated liquid dispersing agent, and the resultingdispersion was diluted to a volume of 100 ml. with water. Test fabricswere immersed in this dye bath, which was then heated at l0=0 C. for onehour. The fabrics were removed and washed well with soap and water. Inthis manner, nylon and wool were dyed a tan color and rayon was dyedbrown.

Since obvious modifications and equivalents in the invention will beevident to those skilled in the chemical arts, I propose to be boundsolely by the appended claims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A compound or" the formula where each of R and R taken singly has upto 10 carbons and is selected from the group consisting of hydrocarbonand hydrocarbon bearing a substituent selected from the group consistingof -OR", CN, OH and -COOR", R being alkyl of 16 carbons, and R and Rattached to the same nitrogen together form a divalent group selectedfrom the class consisting of alky-lene and oxaalkylene of 4-10 carbons.

2. 1,2-dicyano-1,2-bis(N,N-dimethylthiocarbarnylthio)- ethylene.

3. 1,2-dicyano 1,Z-bis(N,N-diethylthiocarbamylthio)- ethylene.

4. 1,2 dicyano 1,2 bis-(2,6-dimethylmorpholinothiocarbamylthio ethylene.

5. 1,2 dicyano 1,2 bis(N,N diisopropylthiocarba mylthio) ethylene.

6. 1,2 dicyano 1,2 bis (piperidinothiocarbonylthio)- ethylene.

7. 1,2 dicyano 1,2 bis(N methyl N phenylthiocar b amylthio -ethylene.

8. A process of preparing1,2-dicyano-1,2-bis-(thiocarbarnylthio)ethylenes which comprisesreacting a salt of the formula \N- C- SM t where each of R and R takensingly has up to 10 carbons and is selected from the group consisting ofhydrocarbon and hydrocarbon bearing a substituent selected from thegroup consisting of OR", -CN, -OH, and -COOR, R" being alkyl of 1-6carbons, R and R joined together form a divalent group selected from theclass consisting of alkylene and oxaalkylene of 4-10 carbons, and M isselected from the group consisting of 'an alkali metal cation, analkaline earth metal cation, the ammonium cation, and a substitutedammonium cation of the formula Rn +H2N/ where each of R and R takensingly is alkyl of 1-6 carbons, and R 'and R together form an alkylenegroup of v r j References Cited by the Examiner 4-5 carbons, with acyclic cyanosulfide selected item the groupc-onsisti ng -o ftetracyano-1,4-dithiin, p-dithiino-[c1- N-ITED :STATES PATENTSisothiazole -'3,5,6- tricarbonitrile and 4,5 dicyano 1,3- 2,792,394 5/57Hlmel at dithiole-A -malononitrile, inan inert organic medium 53,047,546 7/ et Whi h is at least artial solv nt fo the alt d c l'c 1 5V c a? e r 5 an ye 1 FOREIGN PATENTS cyanosulfide. 1 v

9. A proce-ss of claim 8 conducted at a temperature 1,060,655 7/59Germany.-

' r 10. A process 'of cleiim 8 wherein the cyclic cyano- 10 NICOLAS IZ QExaminersu lfide is tet-racyanO IA-dithiin. V

Patent No. 5,197,472 July 27, 1965 Column 10, line 46,

for "carbamylthio" carbonylthio -o read Signed and sealed this 8th dayof March 1966.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner ofPatents

1. A COMPOUND OF THE FORMULA